Identify $Z$ in the following reaction sequence:
${C_2}{H_5}I$ $\xrightarrow{Alc. KOH} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{KCN} Z$

What is the product of the following reaction?

$17 \, mg$ of a hydrocarbon ($M$.$F$. $C_{10}H_{16}$) takes up $8.40 \, mL$ of $H_2$ gas measured at $0^{\circ}C$ and $760 \, mm$ of $Hg$. Ozonolysis of the same hydrocarbon yields acetone,formaldehyde,and a compound with the structure $CH_3-CO-CH_2-CH_2-CHO$. The number of double bonds present in the hydrocarbon is $...........$.

An alkene on ozonolysis gave acetaldehyde. The alkene is:

The reaction conditions used for converting $1, 2$-dibromoethane to ethylene are:

What is the major product of the following reaction?